Tachometer.



w. H. HUNGERFORD.

TACHOMETER. APPLICATION FILED APR. 7. 1914.

1,124,447 Patented Jan. 12, 1915.

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WARREN H. HUNGERFORD, 0F CHICAGO, ILLINOIS, ASSIGNOR T0 FRANK IVI. PETERS, OF

v CHICAGO, ILLINOIS. i

TACHOMETER.

Application filed April 7, 1914.

To all fw/Lom it may concern Be it known that I, WARREN I-I. HUNGER- FORD, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Tachometers, of which the following is a specification.

This invention relates to improvements in tachometers, and refers more particularly to tachometers in which the speed-indication is given by the height of liquid in a sighttube.

In tachometers of the type referred to the liquid is forced up the tube by means of a screw-propeller situated in a reservoir placed below the indicator tube and suitably connected therewith so that rotation of the screw-propeller in the reservoir forces the liquid up the tube a certain height, depending upon the speed of rotation of the propeller.

The salient objects of the present invention are, to provide improved means for calibrating the tachometer without the necessity of making complicated internal adjustments of the device; to provide means whereby the same tachometer may be used for indicating widely varying ranges of speed and at the same time utilizing the Vfull length of the tube over the range of speed desired; to provide an improved method of inserting the sight-tube or removing it in case of breakage; to provide a tachometer which shall be extremely simple in design and economical in construction; and, in general, to provide an improved tachometer of the character described.

My invention consists in the matters hereinafter described and more particularly pointed out in connection with the accompanying drawings, in which- Figure l is an elevation of an approved embodiment of my tachometer looking at the face of the device; Fig. 2 is a longitudinal section taken along the line 2-2 of Fig. l; Fig. 3 is a horizontal sectiontaken along the line 3--3 of Fig. 2; and Fig. L is a horizontal section taken along the Aline 4 4 of Fig. 2.

Referring to the drawings, itwill be seen that the tachometer as a whole consists of a main casting 1 substantially cylindrical' in its general shape, the upper portion of which is fitted with a removable block or cap l2.

Specification of Letters Patent.

Patented J an. l2, 1915.

Serial No. 880,104.

In the lower portion of the casting l is located the pump-chamber 8 the upper end of which is open and communicates with the main reservoir portion of the cylinder 4. The cross-sectional area of the chamber 3 is small compared with the cross-sectional area of the chamber 4, so that the level of the liquid in the reservoir 4 will not vary materially when the level of the liquid in the tube is at various heights. The lower end of the cylindrical casting l is provided with an extension 5 which is bored out and tapped to receive the pivot plug 6 threaded therein. The latter is furnished with a screw-driver slot 7 and is also coned out at the top to receive the lower end of the spindle 8. The other end of the spindle 8 is cylindrical and rotates in a hole bored out in a downwardly extending portion of the top cap 2. The upper end of the spindle 8 terminates a considerable distance short of the upper end 'of the bored hole 9 so as to provide for a considerable amount of end-adjustment for the spindle 8, for a purpose which will hereinafter appear.

The rotary element, which in this case is an rchimedean screw-propeller 10, is suitably secured to the spindle 8 and is of a diameter slightly less than that of the pumpchamber 8. At the lower end of the pumpchamber a conduit l1 leads off and com'- municates with a second conduit 12 leading to the lower end of the sight-tube 13. The latter is seated upon a leather washer 14 situated in a recessed bored-out seat at the upper end of the conduit l2, and the upper end of the sight-tube is prevented from communicating with the open slot 15 by means of la second leather washer 16, the leather washersbeing squeezed tightly in contact with the open ends of the sight-tube by means of a screw-plug 17 which is threaded into the bored and tapped hole in the upper end of the sheath surrounding the sightunscrew the plug 17 and then the tube may be readily extracted vertically without its sheath.

As an approved form of driving means I show a grooved pulley 19 which is mounted on a shaft 20 journaled in an integral bearing provided in the side of the casing. The inner end of the shaft 20 has securely keyed to it a miter gear 21 which meshes with a second miter gear 22 on the vertical spindle 8. A key-way 23 is out longitudinally in the spindle Sand also extends down below the bevel gear 22 a considerable distance, the bevel gear 22 obtaining a driving connection through a short key xed in its hub which engages the longitudinal key-way in the spindle 8. The t of the miter gear 22 on the spindle 8 and the lit of the key in the lkey-way of the spindle is fairly loose so as to permit free longitudinal adjustment of the spindle, the bevel gear remaining stationary.

As will be seen from an inspection of Fig. 1, the speed of rotation is read olf from a scale marked on the casing at the right of the' sight-tube. In order to obviate the necessity of havingto calibrate each taohometer separately and mark it with its own individual scale, the scales are all alike and are printed or engrossed beforehand, and the device is adjusted to make the printed scale read correctly after the tachometer has been completely assembled. This is accomplished by means of a Calibrating by-pass 24, the upper end of which communicates with the mainreservoir and the lower end leads fromv the bottom of the pump-chamber. At the bottom of the by-pass I provide a valve orifice which is adjusted by means of a cone valve plug 25 which is threaded into the outer wall ofthe casing and is furnished with an outside knurled head 26. After the machine has all been finished, the calibration is checked up andv adjusted for various known speeds of the device by turning the knurled head 26 until the height of the liquid in the tube corresponds with the gradation of the particular speed at which the machine is running. Ordinarily it is sufficient to check up the calibration by running the tachometer at a speed approaching theA maximum speed of the device.

The purpose of adjusting the screw-propeller vertically in the pump-chamber will now be explained.r Ordinarily when it is desired-vto make tachometers suitable for registering widely varying speed it is customaryl toyprovide different gear ratios, which have the-effect of causing the machine to run at the same actual speed of rotation of the working spindle, whatever the range of speedv4 desired. In my improved construction,how`ever, I obviate the necessity of providing a large number of diEeI-ent gear ratios by making the screw-propeller adjustable vertically in the pump-chamber. As shown in Fig. 2, the screw-propeller is wholly immersed in the liquid, and the machine as thus illustrated is suitable for registering the lowest range of speed desired. If, however, there arises the necessity of providing for a higher range of speed, this is taken care'of by raising the screw-propeller bodily a sufficient distance so as to permit a portion of the screw to revolve idly in the reservoir above the surface of the liquid, this thus causing a reduction lin the liquid pressureand a corresponding lowering of the liquid in the height of the tube for a given rotary speed. As previously noted, this longitudinal adjustment of the screwpropeller is taken care of by means of the threaded plug 5 in which the lower end of the spindle is pivoted, the upper end of the spindle 8 rising an equal amount in the open ended extension of the bore 9.

I do not wish to be limited to the details of construction shown except as specified in the appended claims.

I claim:

1. In a tachometer, the combination of a liquid reservoir having a vertical pumpchamber at its lower end, a rotary impeller screw mounted vertically withinsaid pumpchamber and adapted to be partially immersed in a supply of liquid in said reservoir, kan indicator-tube connected at one end with the lower end of the pump-chamber and having its upper end connected to the main reservoir above the liquid surface, and means for adjusting the screw-propeller vertically within said pump-chamber.

2. In a tachometer, the combination of a liquid reservoir of comparatively large cross-sectional area, having a pump-chamber at its lower end, a rotary impeller screw mounted within said pump-chamber and adapted to be raised and lowered within the pump chamber to vary the depth of immersion of the impeller within the liquid, and an indicator-tube connected at one end with the lower end of the pump-chamber and having its other end connected to the main reservoir above the liquid surface.

3. In a tachometer, the combination of a liquid reservoir having a vertical pumpchamber formed at its lower end, a rotary impeller mounted within said pump-chamber and adapted to be immersed in a supply of liquid in said reservoir and pump-chamber, an indicator-tube connected at one end with the lower end of the pump-chamber and having its other end connected to the main reservoir above the liquid surface, and a by-pass connection between the upper' and lower portions of said pump-chamber for regulatingV the ow of liquid to said indicator-tube. l j f 4. In a tachometer, the combination. of a liquid reservoir having a vertical pumpchamber formed at its lower end, a rotary impeller mounted within said pump-chamber and adapted to be immersed in a supply of liquid in said reservoir and pump-chambei', an indicator tube connected at one end with the lower end of the pump-chamber and having its other end connected to the main reservoir above the liquid surface, a by-pass between the upper and lower portions of said pump-chamber, and means for regulating the iow of liquid through the by-pass.

5. In a tachometer, the combination of an inclosing casing having a main reservoir and a pump-chamber at the lower end of said main reservoir, an indicator tube having its lower end connected with the lower end of the pump-chamber and its upper end connected with the upper end of the reservoir, a vertical spindle, a screw-propeller mounted on said spindle in said pumpchamber, means for vertically adjusting said spindle and said impeller to vary the depth of immersion of said impeller in a supply of liquid contained in said reservoir, a bypass connection between the reservoir and the lower end of the pump-chamber, and a valve for regulating the flow of liquid through said by-pass.

G. In a tachometer, the combination of an inclosing casing substantially cylindrical in outline, having its axis vertical and having a main reservoir therein with a pump-chamber formed at the lower end of the main reservoir, an indicator tube communicating at its lower end with the bottom of the pump-chamber and at its upper end with the space above the level of the supply of liquid contained within said reservoir, said casing being provided with a slot for eX- posing a portion of the indicator-tube, and with an integral sheath portion on the inside partially surrounding said tube, and means for preventing flow of liquid around the circumferences of the ends of said tube.

7. In a tachometer, the combination of a .liquid reservoir having a pump-chamber at its lower end, a rotary impeller screw mounted vertically within said pump-chamber and Aadapted to be partially immersed in a supply of liquid in said reservoir, an indicator-tube connected at one end with the lower end of the pump-chamber and having its upper end connected to the main reservoir above the liquid surface, and a step bearing for supporting the impeller screw at the bottom of said pump-chamber and vertically adjustable for changing the depth of immersion of said propeller in the liquid.

8. In a tachometer, the combination of a liquid reservoir having a pump-ohamber at its lower end, a rotary impeller screw mounted vertically within said pump-chainber and adapted to be partially immersed in a supply of liquid in said reservoir, an indicator-tube connected at one end with the lower end of the pump-chamber and having its upper end connected with the main reservoir above the liquid surface, said pump-chamber having a projection at its lower end provided with a threaded cylindrical bore, and a threaded step bearing within said threaded bore for supporting the screw propeller and vertically adjustable for varying the depth of immersion of said screw propeller in said liquid.

9. In a tachometer, the combination of a reservoir, a pump-chamber in open communication with the reservoir, a supply of liquid, an Archimedean screw propeller adapted to rotate within said pump-chamber and to project from the open end of said pump-chamber into said reservoir, means for registering variations in the pressure of liquid in said pump-chamber caused by changes in the speed of rotation of said propeller, and means for axially adjusting the position of said propeller in said pumpchamber.

WARREN H. HUNGERFORD.

Witnesses:

C. A. SoANs, E. G. INGERsoLL.

Copies uf this patent may bel nbtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C. f 

